My Mistress quite enjoys having me punish myself and particularly likes me to administer CBT to my own cock and balls.
Mistress has me wear The Curve chastity device 24/7 under my pretty panties so my self punishment often coincides with a release.
I will be told to strip to my panties and go to the playroom. I know that I must get onto my knees on the stone floor and wait. I might have to wait for half an hour but my mind will be spinning when I hear the click of Her boot heels as She enters.
I love to be gagged with Her panties but She enjoys my discomfort in my being gagged with my own so the pink lace is soon filling my mouth.
She will, almost ceremoniously, unlock The Curve and tell me to put my hands behind my head. The cock that has been in the restraint for 2 or 3 weeks will soon be hard and an easy target for Her riding crop.
But my deliciously cruel Mistress will hand me the crop and take up either a bull whip or an equally evil long fibreglass cane.
I will be instructed to whip my cock and if She feels I haven’t done it hard enough, and of course it will never be hard enough, I will receive a stoke from Her whip which will be enough to break the skin.
I will also be instructed to lace a parachute to my balls and hang weights from it and I will be allowed to choose the weight. Mistress will have a weight in mind so I have to try to guess what and put at least that much on, if not I will be told to double the weight.
The inside of my thighs will also be targets for self punishment and I have a Prince Albert piercing that my Mistress finds it fun to have me hang weights from.
However, in my state of serious arousal the pain is soon lost as I drift into ‘sub-space’, it is only later, after Mistress has allowed me to cum and then lick the mess off the floor that the real agony starts.
Mistress will get my cock semi rigid again, with the weights still attached to my now seriously aching balls and hand me the crop again. It really does take a lot of will power and an absolute devotion to Her to beat my now black and blue cock, but of course I do it for Her.

My Mistress took me, as Her maid, to a FemDom event held outdoors, it was primarily a ponyboy event and the ponies were being treated cruelly as one might expect.
My mistress felt that I was far too comfortable in my tradition maids uniform and sensible shoes and had spotted some nettles in the undergrowth.
I was commanded to pull up a single stem about 2 foot in length with my bare hands and roll it into a ball, I then had to lift my skirt, and with supreme effort, stuff the ball down the front of my panties and straiten out my skirt. Mistress then helped the nettles do their evil work to my cock and balls by lashing me with the riding crop She held.
Not content, Mistress had me make a second bunch which went down the back of my panties and then two further bunches went under the breast forms in my bra.
My comfortable job of serving the ladies food and drink suddenly became a nightmare. Every time I moved the stinging got worst, my cock and balls, my bottom and my nipples were on fire but it was two full hours before Mistress allowed me to remove the weeds and 24 hours before the tingling eventually stopped.
I’m sure I could only have done it because of my absolute devotion to Her.
gwendoline

If the matter is cam-session, as a Dom, you have to make the sub in front of you suffer by self-torture. These are some of my directives:

-Getting arms useless for awhile-
Tools: Just a straight thing as ruler or cane.
Instruction: Arms up to the level of shoulders, straigthly forwarded; palms are looking to the floor; put that ruler (or sth. else) on and between your both hands and wait till my second command.
Conclusion: A pair of tired and suffered arms. So simple but I like this, especially when slave cannot realise how a painful activate it is at first and taking it easy. You can observe the decreasing level of the ruler second by second.

-Burning the soles-
Tools: Wax, cigarette lighter or another heater; a metal spoon (can be replaced with sharp a pin).
Instruction: Heat that spoon well on the wax till I command to stop (then waiting for the hot spoon); well, now put your right (left) foot on a place I can easily watch; now show me your sole; ok, you may start to beat your soles with that hot spoon (after that, let yourself enjoy these scenes, afraid eyes, little touches but unbearable pain can be read on sub's face). ; ok, now heat the handle of that spoon till I say "OK" (again waiting); OK sub, now pass that handle throught between each of your toes slowly (here is another funnygame with your toy-slave).
Conclusion: A burned sole, maybe a pair of wet eyes, soot black on sole: I love this...

For sure, one other funny game on cam is wax dropping, you may plan various painful activities with a pair of waxes.

For myself, I am generally limited by kids in the house, so things that are noisy are out. Also, things prone to leave marks and things which take long are generally only possible in rare circumstances.

Nipple clamps (I have nasty weighted ones meant to hold table clothes down during windy picnics) are my usual choice. Sometimes these are intensified by the use on a TENS unit conected to them. Other times, when the nips need to heal from the cuts/punctures left by the cruel clips, milder clamps are used with the TENS unit.

On occasion, the TENS unit is also used on the penis and testicals.

On very rare occasions I have the opportunity to use extended bondage (via an ice release), but that is rare.